Re: [Gnustep-cvs] r26723 - in /libs/base/trunk: ChangeLog Headers/Additions/GNUstepBase/config.h.in Source/GSFFIInvocation.m configure configure.ac

[Hubert Chathi]

On Sun, 29 Jun 2008 09:54:56 +0200, David Ayers <address@hidden> said:

> Hello David David Chisnall schrieb:
>> I think calling mmap directly is the wrong solution here.  You should
>> be using valloc() with the requested size rounded up to the nearest
>> page size, and then use mprotect to set it as executable.  Note that
>> most sane operating systems (and Vista) are moving to W^X, so you
>> need to set it as writeable while creating it, then executable while
>> using it (i.e.  call mprotect immediately before the return).
>> 

>My man page for vmalloc states:
>        The obsolete function valloc() allocates size bytes and returns
> a pointer to the allocated memory.  The memory address will be a
> multiple of the page size.  It is equivalent to
> memalign(sysconf(_SC_PAGESIZE),size).

Heh.  My man page for memalign says:
,----
| The obsolete function memalign() allocates size  bytes  and  returns  a
| pointer to the allocated memory.  The memory address will be a multiple
| of boundary, which must be a power of two.
`----
and implies that posix_memalign should be used instead.  From what I can
gather, "ptr=valloc(size)" is equivalent to
"posix_memalign(&ptr,sysconf(_SC_PAGESIZE),size)", but don't quote me on
that.

Hubert